This invention relates to a refrigerant compressor for use in an air conditioning system for automotive vehicles, and more particularly to a vane compressor which has a suction port and a discharge port both located at the same axial side thereof.
Vane compressors, which are widely employed as refrigerant compressors in air conditioning systems for automotive vehicles, typically comprise a pump assembly mainly composed of a pump housing disposed within a casing formed by a generally cylindrical covering and a front head joined together, and a rotor and vanes accommodated within the pump housing. A suction port, through which refrigerant is introduced into the compressor, is formed in an upper portion of a front head located at a front part of the compressor and disposed to communicate with pump working chambers on suction strokes, while a discharge port, through which refrigerant is discharged from the compressor, is formed through an upper portion of the covering located at a rear part of the compressor for communication with pump working chambers on compression strokes. The compressor is adapted to be connected with the refrigerating circuit of an associated air conditioner by means of connectors mounted in the suction port and the discharge port.
However, in many automotive vehicles in which such vane compressors are to be installed, auxiliary equipments driven by the engine, such as a generator, an oil pump, and an air pump, are usually arranged at a front side of the compressor, providing difficulties in securing a sufficient space for accommodating these auxiliary equipments as well as a suction refrigerant hose or pipe connected to the suction port located at a front portion of the compressor.
Such disadvantage can be overcome by arranging the suction port together with the discharge port at a rear portion of the compressor casing, for instance. To realize this, it is desirable to also arrange the suction chamber close to the suction port at the rear portion of the compressor in order to avoid an increase in the flow resistance that the suction refrigerant undergoes, and accordingly to avoid a drop in the suction volumetric efficiency. However, if the discharge pressure chamber formed in the rear portion of the compressor is designed smaller in volume so as to provide a space for the suction chamber there, it can result in increased pulsation of discharge refrigerant being supplied into the refrigerating circuit, poor separation of lubricating oil from the discharge refrigerant, etc. On the other hand, if the volume of the discharge pressure chamber remains unchanged, it will necessitate increasing the size of the compressor.